6 occlusion

6 occlusion

3. INTRODUCTION

•Occlusion of the complete denture has a
direct effect on the success or failure of the
treatment

• So the occlusal scheme and concept should
produce masticatory efficiency, without
negative effect on the esthetic value of the
denture, the health of the supporting
tissues, and comfort of the patient

4. Terminology:
Occlusion:
•It is the act or process of closure or of being closed
or shut off.

•The relationship between the occlusal surfaces and
incisal edges of the maxillary and mandibular teeth
when they are in contact
•It is a static position (relation) when the jaws are
centrically or eccentrically related
(the way the teeth come together and function together)

5. Terminology:
Articulation:
Relationship between the occlusal surfaces of
the maxillary and mandibular teeth during
function (Dynamic relation)

6. Terminology:
Centric occlusion:
Occlusion of the opposing occlusal surfaces that provide the
maximum planned contact (Intercuspation) when the mandible is in
centric relation to the maxilla.

Eccentric occlusion: ( Protrusive occlusion & lateral
occlusion)
Describe the relation of opposing occlusal surfaces when the
mandible is moved forward or laterally

7. Terminology:
Balanced occlusion
-simultaneous contact of maxillary & mandibular teeth
on the right ,the left , in the anterior & posterior
occlusal areas when the jaws are in centric or
eccentric relation ( static position)
-simultaneous means even contact at the same time

8. Balanced articulation ( Balancing Sliding Occlusion):
Continuous sliding contact of maxillary & mandibular
cusps during all closed grinding movements of the
mandible (dynamic), without interference
Smooth Mandibular movement from centric to
eccentric positions & vise versa
Terminology:

9. Terminology:
The working side:
The side to which the mandible move in order to
break up a bolus of food,
The opposite side is termed The balancing side
(non working side)

10. Natural teeth Artificial teeth
-Periodontal ligament supports
teeth
-no periodontal ligament
-Function independently -function as group

- Bilateral balance, not necessary if
present considered pathological
-Bilateral balance is mandatory for
denture stability
-Non vertical forces well
tolerated
-Non vertical forces are
damaging to supporting tissues
Important differences between natural
and artificial occlusion

11. Incising doesn’t affect posterior
teeth
Incising affects all teeth on the
base
Second molar is favoured position
for mastication
Heavy pressures of mastication in
second molar region tilts base&
shifts it on inclined surface

Proprioceptive impulses give feed
back to avoid prematurities &
interferences-so a habitual
occlusion away from centric is
established
No feed back of proprioceptive
impulses& So any prematurity can
not be determined will shift
denture base
Important differences between natural
and artificial occlusion

13. Types of complete denture Posterior teeth
according to their occlusal morphology

1- anatomic ( 30-33˚ cusp incline)

2- semianatomic (20˚ cusp incline)
3- nonanatomic (0- dgree)

14. The following should be considered when
choosing the posterior teeth

1- Ridge morphology.

2- Arch relationship.

3- Esthetics.

4- Patient’s age, and neuromuscular coordination.

5- Previous denture- wearing experience.

6- Concept of occlusion.

15. Occlusal Concepts Of Complete dentures
I- Concept of occlusal balance(balanced occlusion):
occlusal contact of the opposing teeth in centric and eccentric
occlusion of the mandible within the functional range of jaw
movement ( Bilateral, simultaneous, anterior and posterior
occlusal contact of teeth in centric and eccentric positions)

II- Concept of Non occlusal balance (non balanced
occlusion):
maximum Occlusal contact of the opposing teeth in centric
occlusion only without contact in eccentric occlusion ………..

( N.B. When & how many no. teeth contact occur , Enter bolus
exit balance)

16. Balance in relation to complete denture:

This mean a state of equilibrium of the denture bases in
relation to their supporting structure when the opposing teeth
contact and there is a resultant forces
There are two types of balance which interact to stabilize the
denture :

1)Lever balance: dependant on tooth position as related to its
base

2)Occlusal balance: dependant on tooth contact

17. 1) Lever balance :
The larger the ridge, the closer the teeth to the
ridge, The more lingual the teeth in relation to
the ridge crest, and the more centered the force
of occlusion antero-posteriorly……………..

more Lever balance and the
greater the stability of the base.

18. Equilibrium of the base on its supporting
structures when a bolus of food is interposed
between the teeth on one side and a space exist
between the teeth on the opposite side
Unilateral lever balance :
(Inter-bolus exit balance)

19. 1. Placing the teeth over the ridge or slightly lingual
to it.
2. Denture base area covers as wide area on the
ridge as possible.
3. Placing the teeth as close to the ridge as other
factors will permit.
4. Using as narrow a buccolingual width occlusal
table as practical.
Functional lever balance , to stabilize the
denture during mastication:

20. 2) Occlusal balance:

To create bilateral contacts from the centric to all
eccentric position, that are free from interferences,
smooth, uniform and in harmony with movement of
the mandible. Such contacts provide stabilizing
forces to the denture bases on their basal seat.

-Contact of opposing teeth in the working and
balancing sides when the mandible move laterally
- minimum three point of contact (one ant. And two
post. L & R)

21. Factors that affect Balanced
Occlusion
•There are five factors involved in eccentric occlusal
balance in complete denture to achieve simultaneous
gliding occlusal contacts from centric occlusion to
eccentric occlusal position.( Hanau Quint)
1- Inclination of the condylar guidance (C.G)
2- Inclination of the Incisal guidance (I. G)
3- Inclination of the cusps (Cusp height) ( C.H)
4- Orientation of the occlusal plane ( O. P)
5- Orientation of the Compensating curve ( C. C)

22. Factors that affect Balanced
Occlusion
Inclination of the condylar guidance & inclination of
the incisal guidance are the two most important
factors as they control the movement of the
articulator.

The remaining three factors ( orientation of the
occlusal plane, inclination of the cusps, and
compensating curve) are arranged to attain
harmony between all five factors to the articulator
movement.

23. 1-Condylar guidance

24. 2- Incisal guidance

25. 3- Cusp height and inclination

26. 4- PLANE OF OCCLUSION
(OCCLUSAL PLANE)

27. 5- COMPENSATING CURVE
Curve of Spee
Curve of Wilson
Curve of Monson

28. I-Balanced Occlusal concept
A- With anatomic teeth ( Bilateral balanced occlusion)

B- With Modified anatomic teeth (Lingualized occlusion)

C- With non anatomic teeth:
- Compensating curves
- Tilting the second molars
- Balancing ramp

29. Non-anatomic teeth for balanced
occlusion


1.Arrange the teeth in compensating curve

2. Tilting the second molar to create an inclined plane

3. Balancing ramp creation

30. 1- Zero Degree Teeth with a Compensating Curve

31. 2. tilting the second molar to create an inclined plane

32. 3-Balancing ramp:
Setting up the teeth in a flat
plane and utilize a balancing
ramp just distal to the second
molar.

33. II-Non-Balanced Occlusal concept
1- Neutro-centric occlusion ( monoplane occlusion)

2- Lingualized occlusion

34. II- NEUTRO-CENTRIC
OCCLUSION
•Neurocentric to denote two objectives in
denture construction.
A- Neutralization of inclines.

B- Centralization of occlusal forces acting on
the denture foundations.

35. •Five factors are involved, to achieve
these 2 objectives:
•Position of Posterior teeth in a central position
•Proportion of the teeth 40% reduction in the width
•Plane of occlusion is parallel with the mean
denture foundation area
•Form devoid of projecting cusps
•Number of teeth reduction in number

36. Neutrocentric concept:
a). Non-anatomic teeth
b). Plane of occlusion parallel to the residual
ridge.
C).No compensating curves, teeth are set flat
d). Maxillary & mandibular teeth arranged
without any vertical overlap.
(e). Complete intercuspation between the
upper & lower posterior teeth except second
molar.
(f).Narrow teeth selected to decrease occlusal
forces.

37. X
•The patients should
avoid incising with their
anterior teeth

38. Advantages of Neutro-centric occlusion:

• Simple Does not require precise records.
•By removing any inclines, lateral destructive
forces on residual ridges is reduced.
•Easier to adjust.
•Freedom in CR ( CR, CO)
•Crossbite patients, and class II, III cases
• good in patient with poor ridges

39. Disadvantages of Neutro-centric occlusion:
-Least esthetics

- position of the teeth more lingual may affect
tongue, and cheeck function

- decrease masticatory efficiency

- Christensen’s phenomenon ( no balance)

40. III- LINGUALIZED
OCCLUSION
This type of occlusion utilize the maxillary lingual
cusps as the centric holding cusps oppose mandibular
teeth with zero degree or shalllow cusp incline ( for
non balanced, or balanced arrangement)
To maintain the esthetic and food penetration
advantages of the anatomic form while maintaining
the mechanical freedom of the nonanatomic form

41. Reducing the efficiency of the lower buccal cusps,
Vertical forces are centralized on the mandibular
teeth. thus directing the forces to the lingual side of
the lower ridge crest to encourage lever
stability of the lower denture.

42. Indicated in patient with high priority on esthetics but
non anatomic teeth indicated eg.:
-Severe alveolar bone resorption.
- displaceble tissues.
- class II & III jaw relation.
-Parafunctional habits ( bruxism, clenching, grinding)
III- LINGUALIZED
OCCLUSION

43. •Aesthetics
•Cusps – better mastication
•Records – less precise
•Stability in lateral excursions
•Reduced lateral forces & centered vertical force
•One contact point ( mortar and pestle )
•Can be used in a variety of situations
“lingualized occlusion is an occlusion for all
saesons”


III- LINGUALIZED
OCCLUSION
Advantages:

44. The following principles of occlusion for complete dentures are
generally accepted:

1. Complete denture patients must make initial and complete
occlusal contact while in centric relation. This is called centric
occlusion.
2. All anterior and posterior denture teeth inclines and surfaces
must function as a “unit" during excursive movements.
3. Any prematurity preventing the movements described in
principles 1 and/or 2 must be eliminated.
4. Significant disclusion of the posterior denture teeth when a
patient protrudes is contraindicated.
5. Anterior tooth contact is contraindicated in centric occlusion.
Conclusion

45. Conclusion
Many occlusal schemes have
been proposed over the
years. Most schemes when
correctly used gives
satisfactory results. The
result is satisfactory if the
patient gets better
function, esthetics &
comfort without any
adverse changes in denture
foundation.